Table 5.

Lowest parotid doses achieved using IMRT and VMAT, while maintaining all other plan objectives. TNM stages are given for each patient

		Mean parotid dose (Gy)
	Stage	IMRT VMAT	$\Delta (\mathit{\text{IMRT}}-\mathit{\text{VMAT}})$
P1	${\mathrm{T}}_3{\mathrm{N}}_2$	19.4	19.1	0.3
P2	${\mathrm{T}}_1{\mathrm{N}}_2$	18.3	16.7	1.6
P3	${\mathrm{T}}_2{\mathrm{N}}_3$ a	13.9	13.8	0.1
P4	${\mathrm{T}}_2{\mathrm{N}}_1$	25.0	23.8	1.2
P5	${\mathrm{T}}_2{\mathrm{N}}_1$ a	20.6	15.5	5.0
P6	${\mathrm{T}}_3{\mathrm{N}}_1$ a	18.8	17.2	1.6
P7	${\mathrm{T}}_2{\mathrm{N}}_2$ a	23.4	21.5	1.9
P8	${\mathrm{T}}_3{\mathrm{N}}_2$	20.5	15.6	4.9
P9	${\mathrm{T}}_2{\mathrm{N}}_1$	19.1	13.1	5.9
P10	${\mathrm{T}}_3{\mathrm{N}}_1$ a	16.7	13.9	2.7
Average		19.6	17.0	2.5